Compact broadband low-coupling tri-polarized dielectric resonator antenna based on inhomogeneous dielectric

Abstract

The invention discloses a compact broadband low-coupling tri-polarization dielectric resonator antenna based on a non-uniform medium, a pair of orthogonal horizontal polarization TEx and TEy resonant modes is excited in the dielectric resonator antenna by utilizing differential feed, the frequency points of the TE111 and TE113 resonant modes of a dielectric resonator are adjusted to be close to each other, and the directional diagrams of the two modes are similar, so that the frequency points of the TE111 and TE113 resonant modes of the dielectric resonator are close to each other. The working bandwidth of the antenna is effectively improved; on the basis, a probe is inserted into the center of the dielectric resonator to excite a vertical polarization TM011 mode of the dielectric resonator, the working frequency bands of the three modes are highly overlapped, and the design of the broadband tri-polarization antenna is realized; meanwhile, the dielectric block with the dielectric constant higher than that of the original dielectric is embedded into the dielectric resonator, so that the working bandwidth of the antenna is increased; the annular gap is etched on the floor around the probe, so that the coupling among the ports is reduced; according to the invention, the tri-polarization common bandwidth reaches 47.7%, the size is 0.326 * 0.326 * 0.326 lambda03, and the bandwidth area ratio reaches 449% / lambda02.

Description

Technical Field

[0001] The invention relates to the field of antennas of communication technology, and in particular to a compact broadband low-coupling tri-polarized dielectric resonator antenna based on a non-uniform medium. Background Art

[0002] With the continuous development of mobile communication technology, MIMO (Multiple-Input Multiple-Output) technology, which increases the channel capacity by increasing the number of antennas, has played an increasingly important role in modern mobile communications. From 4 antennas and 8 antennas in the 3G era to dozens and hundreds of antennas in the 5G / 6G era, MIMO has also gradually evolved from traditional small-scale systems to large-scale and ultra-large-scale systems. Large-scale MIMO systems have put forward new requirements for the miniaturization, compactness, low coupling, and easy production of antenna units. The tri-polarized antenna can realize the multiplexing of three polarization states of electromagnetic waves on the same radiating unit. Applying it to the MIMO communication system can increase the channel capacity exponentially. As a new type of antenna, the dielectric resonator antenna has attracted the attention of researchers due to its small size, high radiation efficiency, rich resonance modes, and high design freedom. Therefore, designing a miniaturized and compact tri-polarized dielectric resonator antenna will have great application prospects in tri-polarized MIMO systems.

[0003] In order to improve the information transmission rate of the communication system, antenna bandwidth is a characteristic that researchers must pay attention to. Since the tri-polarized antenna has three ports, it is necessary to ensure that the working frequency bands of each port remain overlapping, and the coupling between ports in the public working frequency band is as small as possible. Although there are many solutions for existing broadband dual-polarized antennas, on this basis, how to add a third polarization and simultaneously obtain a larger public bandwidth and lower coupling characteristics between the three polarization ports is a major problem in the current tri-polarized antenna design.

[0004] Reference [1] proposed a tri-polarized dielectric resonator antenna based on a balanced feed structure. The antenna excites a pair of mutually orthogonal HE 11δ mode and the vertical polarization mode of the monopole. Four rectangular slots are etched on the antenna ground, and are fed by two pairs of equal-length feed lines. The monopole antenna feeding port adds an extended ground at the bottom of the substrate for welding of the SMA interface. The relative bandwidth of the antenna is 15.9%, and the size of the dielectric block is π×0.12 2 ×0.20λ0 3 Due to the balanced feeding structure, the antenna pattern, cross-polarization ratio, and coupling between ports all perform well, but the bandwidth is still relatively limited.

[0005] Reference [2] proposed a low-profile three-port tri-polarized dielectric resonator antenna. The cylindrical dielectric resonator antenna is fed by a feed line through four gaps close to a ring. Two of the ports can excite a pair of orthogonal HE by feeding into the symmetrical gaps. 13δ mode, the third port provides equal amplitude and same direction signal input to the four slots, which can stimulate the TM of the dielectric resonator 02δ mode, producing a vertically polarized radiation pattern. The size of the antenna dielectric block is π×0.59 2 ×0.10λ0 3 , with a relative bandwidth of 5.1%. Although the antenna profile is only 0.10λ0 in height, the low common bandwidth and its large lateral size still limit its application scenarios.

[0006] Reference [3] proposed a three-polarized rectangular dielectric resonator antenna. x δ11 Mode, asymmetric TE y 1δ1 The mode realizes two orthogonal horizontal polarizations, symmetrical TE y 1δ1 The mode realizes quasi-omnidirectional vertical polarization. The three modes are excited by the differential probe, the central slot and the peripheral slot respectively. The size of the antenna dielectric block is 0.29×0.31×0.13λ0 3 , the relative bandwidth is only 3.4%.

[0007] The literature [1] is Deng C, Feng Z, He Y.Hybrid cylindrical dielectric resonatorantenna with monopole for tri-polarized operation[J].Microwave and OpticalTechnology Letters, 2016, 58(3):635-638.

[0008] Document [2] is Fang XS, Luo L, Xu YJ, et al. Design of the low-profile tri-polarized diversity cylindrical dielectric resonator antenna utilizing high-order HEM 13δand TM 02δmodes[J]. IEEE Transactions on Antennas andPropagation, 2023,71(11):9060-9065..

[0009] Document [3] is Zhang B, Ren J, Luan Y, et al. Three-port three-polarized dielectric resonator antenna with omnidirectional radiation [J]. IEEE Antennasand Wireless Propagation Letters, 2023, 22(12): 3122-3126.

[0010] In summary, the shortcomings of existing three-polarized dielectric resonator antennas and the challenges they face in design and application are as follows:

[0011] (1) The resonant modes of antennas with different polarizations are difficult to operate in the same frequency band and it is difficult to obtain a large bandwidth at the same time, so the common bandwidth is small;

[0012] (2) The complex feeding network has a significant impact on the antenna impedance matching, resulting in a smaller bandwidth;

[0013] (3) The coupling between some ports within the working bandwidth is high, causing the antenna's radiation pattern to be distorted. Summary of the invention

[0014] Purpose of the invention: In order to solve the shortcomings of existing broadband dual-polarization dielectric resonator antennas and the challenges in design and application, the present invention proposes a compact broadband low-coupling tri-polarization dielectric resonator antenna based on non-uniform medium, which solves the problems of complex feeding structure and low bandwidth of existing tri-polarization dielectric resonator antennas, and realizes broadband tri-polarization radiation performance in a relatively compact structure, which can be applied to wireless communications, large-scale MIMO antenna arrays and other fields.

[0015] Technical solution: A compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium, comprising: a dielectric substrate, a dielectric resonator, a first coaxial probe, a second coaxial probe, a third coaxial probe, a fourth coaxial probe, a fifth coaxial probe, a first Wilkinson power divider, a second Wilkinson power divider, a first feeding port, a second feeding port, a third feeding port and a floor;

[0016] The dielectric substrate is arranged on the lower surface of the floor, and the dielectric resonator is arranged on the upper surface of the floor; the first Wilkinson power divider and the second Wilkinson power divider are arranged on the lower surface of the dielectric substrate;

[0017] The dielectric resonator is a horizontal radial layered dielectric structure, which is composed of a cylindrical dielectric embedded in a rectangular dielectric resonator, and the dielectric constant of the cylindrical dielectric is higher than the dielectric constant of the surrounding dielectric;

[0018] The first coaxial probe is inserted into the center of the dielectric resonator, and the second coaxial probe, the third coaxial probe, the fourth coaxial probe and the fifth coaxial probe are respectively inserted into the interior of the dielectric resonator and close to the edge of the dielectric resonator;

[0019] Circular gaps are etched on the peripheral floors of the second coaxial probe, the third coaxial probe, the fourth coaxial probe, and the fifth coaxial probe;

[0020] The second coaxial probe and the fourth coaxial probe are symmetrically arranged to form a differential feed pair, the third coaxial probe and the fifth coaxial probe are symmetrically arranged to form another differential feed pair, and the two differential feed pairs are orthogonally arranged;

[0021] The first feeding port directly feeds the first coaxial probe to stimulate vertical polarization radiation TM with the polarization direction being the z-axis direction. 011 model;

[0022] The second feed port is connected to the input end of the second Wilkinson power divider, and the output end of the second Wilkinson power divider is connected to a differential feed pair to stimulate TE y 111 TE y 113 Mode; the third feed port is connected to the input end of the first Wilkinson power divider, the output end of the first Wilkinson power divider is connected to another differential feed pair, and the TE is stimulated x 111 TE x 113 Mode;TE 111 and TE 113 The directional patterns of the modes are similar and the resonant frequencies are close, which increases the bandwidth of the antenna and realizes three mutually orthogonal polarization modes in the same radiator.

[0023] Furthermore, holes are opened at the contact points between the second coaxial probe, the third coaxial probe, the fourth coaxial probe, and the fifth coaxial probe and the floor.

[0024] Furthermore, the cylindrical dielectric resonator has the same height as the rectangular dielectric resonator.

[0025] Furthermore, there is a certain gap between the first coaxial probe and the dielectric resonator.

[0026] Furthermore, the first Wilkinson power divider and the second Wilkinson power divider implement differential feeding.

[0027] Further, the first Wilkinson power divider and the second Wilkinson power divider each include a first microstrip line, a quarter-wavelength microstrip line, a second microstrip line and a limiting resistor;

[0028] For any one of the first and second Wilkinson power dividers, its input end is connected to the first microstrip line, and then connected to two quarter-wavelength microstrip lines connected in parallel. A limiting resistor is connected to the ends of the two quarter-wavelength microstrip lines, and finally connected to the output end by the second microstrip line. The length of the second microstrip line connected to the two output ends differs by half of the microstrip line waveguide wavelength, so that the output signal power of the two output ends is the same and there is a phase difference of 180 degrees. The two output ends are respectively fed to symmetrical coaxial probes to achieve differential feeding.

[0029] Furthermore, the first microstrip line and the second microstrip line are both microstrip lines with a characteristic impedance of 50 ohms.

[0030] Furthermore, the quarter-wavelength microstrip line is a quarter-wavelength microstrip line with a characteristic impedance of 70.7 ohms.

[0031] Furthermore, the limiting resistor is a 100 ohm limiting resistor.

[0032] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0033] (1) The present invention first uses differential feeding to excite a pair of orthogonal TE x and TE y resonant mode and adjust the TE of the dielectric resonator 111 and TE 113 The resonant mode frequencies are close to each other. Since the radiation patterns of the two modes are similar, this will effectively increase the working bandwidth of the antenna. On this basis, a probe is inserted into the center of the dielectric resonator to stimulate the TM 011 mode, the radiation performance of this mode is similar to that of a vertically placed monopole antenna. At the same time, a broadband vertically polarized radiation mode is realized by using a non-uniform dielectric structure. The working frequency bands of the three modes are highly overlapped, realizing the design of a broadband tri-polarized antenna.

[0034] (2) The present invention changes the horizontal radial dielectric distribution of the dielectric resonator by embedding a dielectric block with a higher dielectric constant than the original dielectric inside the dielectric resonator, thereby changing the field distribution in the resonant cavity of the dielectric resonator antenna at different frequencies; when the antenna is at a lower resonant frequency, the dielectric resonator as a whole maintains a resonant state, and the dielectric constant is the equivalent dielectric constant of the non-uniform medium; when the frequency increases, the horizontal radial layered structure can suppress the generation of high-order modes. At this time, at the high-frequency resonance point, the energy in the cavity is mainly concentrated in the high-dielectric constant dielectric block, and the high-dielectric constant dielectric block plays the role of mainly resonating and radiating outward, ultimately increasing the working bandwidth of the antenna;

[0035] (3) The present invention proposes that there is a certain gap between the coaxial probe inserted in the center and the dielectric resonator, and the impedance matching effect between the coaxial probe and the dielectric resonator is improved by adjusting the gap distance;

[0036] (4) The present invention proposes to etch circular gaps in the floor around the probes, thereby reducing the coupling between the ports; when one probe of the antenna is excited, the circular gaps around the other probes will change the field distribution around the surrounding probes, reducing the size of the field around the probes, thereby reducing the mutual influence between the probes and increasing the isolation between the ports;

[0037] (5) The present invention proposes to use a Wilkinson power divider as a feeding network for a dielectric resonator, and to adjust the phase difference of the two output signals to be kept close to 180 degrees in the working frequency band of the dielectric resonator by changing the transmission line length at the output end of the Wilkinson power divider, thereby realizing differential feeding and maintaining a large bandwidth of the antenna;

[0038] (6) The present invention realizes low coupling characteristics between the second and third ports through differential feeding. Differential feeding is equivalent to forming a virtual ground at the center position between the two feeding probes, so that the field distribution under the two polarizations is more orthogonal and less likely to affect each other, thereby reducing the coupling between the two ports;

[0039] (7) The tri-polarized dielectric resonator antenna proposed in the present invention meets the application requirements of miniaturization and compactness. The proposed tri-polarized antenna has an operating frequency range of 1.77 to 2.88 GHz, a common bandwidth of 47.7%, and an isolation between three ports of 15 to 48 dB. The size of the dielectric resonator is 0.326×0.326×0.326λ0 3 , bandwidth-to-area ratio reaches 449% / λ0 2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of the structure of a compact broadband low-coupling tri-polarized dielectric resonator antenna based on a non-uniform medium proposed by the present invention; wherein: Figure 1 (a) is the overall structure diagram of a compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform media. Figure 1 (b) is a side view of a compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium;

[0041] Figure 2 The S parameter diagram of each port of a compact broadband low-coupled tri-polarized dielectric resonator antenna based on non-uniform medium proposed by the present invention;

[0042] Figure 3The magnetic field distribution diagram of the bottom surface of the dielectric resonator when the first feeding port of the compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium proposed by the present invention is separately excited and works at different frequencies; wherein, Figure 3 (a) is the distribution diagram of the magnetic field size at the bottom of the dielectric resonator when working at 1.8 GHz. Figure 3 (b) is the distribution diagram of the magnetic field size at the bottom of the dielectric resonator when working at 2.2 GHz. Figure 3 (c) is the distribution diagram of the magnetic field size at the bottom of the dielectric resonator when working at 2.5 GHz. Figure 3 (d) is the distribution diagram of the magnetic field size at the bottom surface of the dielectric resonator when working at 2.8 GHz;

[0043] Figure 4 This is a diagram of the electric field distribution on the surface of the dielectric resonator when the second feeding port of the compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium proposed by the present invention is excited separately and operates at different frequencies; wherein, Figure 4 (a) is the surface electric field distribution diagram of the dielectric resonator when working at 1.8 GHz. Figure 4 (b) is the surface electric field distribution diagram of the dielectric resonator when working at 2.2 GHz. Figure 4 (c) is the surface electric field distribution diagram of the dielectric resonator working at 2.5 GHz. Figure 4 (d) is the surface electric field distribution diagram of the dielectric resonator when working at 2.8 GHz;

[0044] Figure 5 This is a diagram of the electric field distribution on the surface of the dielectric resonator when the third feeding port of the compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium proposed by the present invention is excited separately and works at different frequencies; wherein, Figure 5 (a) is the surface electric field distribution diagram of the dielectric resonator when working at 1.8 GHz. Figure 5 (b) is the surface electric field distribution diagram of the dielectric resonator when working at 2.2 GHz. Figure 5 (c) is the surface electric field distribution diagram of the dielectric resonator working at 2.5 GHz. Figure 5 (d) is the surface electric field distribution diagram of the dielectric resonator when working at 2.8 GHz;

[0045] Figure 6 The present invention provides a compact broadband low-coupled tri-polarized dielectric resonator antenna based on a non-uniform medium and an antenna electric field pattern when the first feeding port is excited alone at 1.8 GHz; wherein: Figure 6 (a) in the figure is the XOZ plane. Figure 6 (b) is the XOY plane;

[0046] Figure 7 The present invention provides a compact broadband low-coupled tri-polarized dielectric resonator antenna based on a non-uniform medium, and an antenna electric field pattern when the first feeding port is excited alone at 2.2 GHz; wherein: Figure 7 (a) in the figure is the XOZ plane. Figure 7 (b) in the figure is the XOY plane;

[0047] Figure 8 The present invention provides a compact broadband low-coupled tri-polarized dielectric resonator antenna based on an inhomogeneous medium and an antenna electric field pattern when the first feeding port is excited alone at 2.5 GHz; wherein: Figure 8 (a) in the figure is the XOZ plane. Figure 8 (b) in the figure is the XOY plane;

[0048] Fig. 9 The present invention provides a compact broadband low-coupled tri-polarized dielectric resonator antenna based on a non-uniform medium, and an antenna electric field pattern when the first feeding port is excited alone at 2.8 GHz; wherein: Fig. 9 (a) in the figure is the XOZ plane. Fig. 9 (b) in the figure is the XOY plane;

[0049] Fig.10 The present invention provides a compact broadband low-coupled tri-polarized dielectric resonator antenna based on a non-uniform medium and an antenna electric field pattern when the second feeding port is excited alone at 1.8 GHz; wherein: Fig.10 (a) in the figure is the XOZ plane. Fig.10 (b) is the YOZ surface;

[0050] Fig.11 The present invention provides a compact broadband low-coupled tri-polarized dielectric resonator antenna based on a non-uniform medium, and an antenna electric field pattern when the second feeding port is excited alone at 2.2 GHz; wherein: Fig.11 (a) in the figure is the XOZ plane. Fig.11 (b) is the YOZ surface;

[0051] Fig.12 The present invention provides a compact broadband low-coupled tri-polarized dielectric resonator antenna based on a non-uniform medium and an antenna electric field pattern when the second feeding port is excited alone at 2.5 GHz; wherein: Fig.12 (a) in the figure is the XOZ plane. Fig.12 (b) is the YOZ surface;

[0052] Fig.13The present invention provides a compact broadband low-coupled tri-polarized dielectric resonator antenna based on an inhomogeneous medium and an antenna electric field pattern when the second feeding port is excited alone at 2.8 GHz; wherein: Fig.13 (a) in the figure is the XOZ plane. Fig.13 (b) is the YOZ surface;

[0053] Fig.14 The present invention provides a compact broadband low-coupled tri-polarized dielectric resonator antenna based on a non-uniform medium, and an antenna electric field pattern when the third feeding port is excited alone at 1.8 GHz; wherein: Fig.14 (a) in the figure is the XOZ plane. Fig.14 (b) is the YOZ surface;

[0054] Fig.15 The present invention provides a compact broadband low-coupled tri-polarized dielectric resonator antenna based on a non-uniform medium, and an antenna electric field pattern when the third feeding port is excited alone at 2.2 GHz; wherein: Fig.15 (a) in the figure is the XOZ plane. Fig.15 (b) is the YOZ surface;

[0055] Fig.16 The electric field pattern of the compact broadband low-coupled tri-polarized dielectric resonator antenna based on a non-uniform medium proposed by the present invention when operating at 2.5 GHz and exciting the third feeding port alone; wherein, Fig.16 (a) in the figure is the XOZ plane. Fig.16 (b) is the YOZ surface;

[0056] Fig.17 The electric field pattern of the compact broadband low-coupled tri-polarized dielectric resonator antenna based on a non-uniform medium proposed by the present invention when operating at 2.8 GHz and exciting the third feeding port alone; wherein, Fig.17 (a) in the figure is the XOZ plane. Fig.17 (b) in the figure is the YOZ surface. DETAILED DESCRIPTION

[0057] The technical solution of the present invention is now further described in conjunction with the accompanying drawings and embodiments.

[0058] like Figure 1As shown, this embodiment discloses a compact broadband low-coupling tri-polarized dielectric resonator antenna based on inhomogeneous medium, which can simultaneously achieve large bandwidth, low coupling and simple structure. The antenna mainly includes a dielectric substrate 1, a dielectric resonator 2 of inhomogeneous medium, a first coaxial probe 3, a second coaxial probe 4, a third coaxial probe 5, a fourth coaxial probe 6, a fifth coaxial probe 7, a first Wilkinson power divider 8, a second Wilkinson power divider 9, a first feeding port 10, a second feeding port 11, a third feeding port 12 and a floor 13. The dielectric resonator 2 is arranged on the floor 13, and the first coaxial probe 3 is inserted into the center of the dielectric resonator 2, with a gap left around it. The second coaxial probe 4, the fourth coaxial probe 6, the third coaxial probe 5 and the fifth coaxial probe 7 each form two pairs of probe groups and are inserted into the inner edge of the dielectric resonator 2. Every two symmetrical coaxial probes form a differential feeding pair. A circular ring gap is etched on the floor 13 around the probes to reduce the coupling between the ports. The contact between each coaxial probe and the floor is processed with an opening. The lower surface of the dielectric substrate 1 is a first Wilkinson power divider 8, a second Wilkinson power divider 9 and a first feeding port 10. The first feeding port 10 uses an SMA coaxial interface with a characteristic impedance of 50 ohms, which directly feeds the dielectric resonator 2 through the first coaxial probe 3. The second feeding port 11 and the third feeding port 12 also use an SMA coaxial interface with a characteristic impedance of 50 ohms, and excite the corresponding coaxial probe to feed the dielectric resonator 2 through the corresponding Wilkinson power divider.

[0059] The dielectric resonator 2 of the inhomogeneous medium of this embodiment is a horizontal radial layered dielectric structure, which is composed of a cylindrical dielectric block with a high dielectric constant embedded inside a rectangular dielectric block with a low dielectric constant. There is a certain gap around the first coaxial probe and the dielectric resonator, that is, an air column is left in the center of the dielectric resonator to adjust the input impedance. This structure changes the dielectric distribution of the dielectric resonator 2 in the horizontal radial direction.

[0060] The first coaxial probe 3 of this embodiment is directly inserted into the center of the dielectric resonator 2, and the other four coaxial probes are respectively inserted near the edges of the four sides of the dielectric resonator 2. Each pair of probes is in a symmetrical position, and each pair of probes is opened at the contact point with the floor. The bottom of the coaxial probe of each pair of probes is directly connected to the transmission line at the output end of the Wilkinson power divider. The second coaxial probe 4 and the fourth coaxial probe 6 are connected to the two output ends of the first Wilkinson power divider 8, and the third coaxial probe 5 and the fifth coaxial probe 7 are connected to the two output ends of the second Wilkinson power divider 9.

[0061] The Wilkinson power divider of this embodiment is composed of multiple sections of microstrip lines and isolation resistors. The input end is connected to a microstrip line with a characteristic impedance of 50 ohms, and then connected to two parallel quarter-wavelength microstrip transmission lines with a characteristic impedance of 70.7 ohms. The ends of the two quarter-wavelength microstrip transmission lines are connected with a limiting resistor of 100 ohms, and finally the signal is output by a microstrip line with a characteristic impedance of 50 ohms. The output power of the signals at the two output ends is the same. The length of the transmission line at the output end differs by half of the wavelength of the microstrip line waveguide, which can achieve a phase difference of 180 degrees between the output signals at both ends. The two output ends are fed to symmetrical probes respectively, that is, differential feeding is achieved.

[0062] The first coaxial probe 3 is inserted into the center of the dielectric resonator 2, which is equivalent to introducing a current source into the center of the dielectric resonator 2, which can excite the TM of the dielectric resonator antenna. 011 Mode. In this resonant mode of the dielectric resonator antenna, the electric field distribution inside the resonant cavity is mainly horizontally radially distributed. By changing the horizontal radial dielectric distribution of the dielectric resonator 2, the field distribution of the resonant cavity at different frequencies can be changed. When the antenna is at a lower resonant frequency, the dielectric resonator 2 as a whole remains in a resonant state. When the frequency increases, the horizontal radial layered structure can suppress the generation of higher-order modes. At this high-frequency resonance point, the energy in the resonant cavity is mainly concentrated in the high-dielectric constant dielectric block. The high-dielectric constant dielectric block mainly resonates and radiates outward, ultimately achieving a broadband vertically polarized radiation mode.

[0063] The second coaxial probe 4 and the fourth coaxial probe 6 introduce two current sources into the dielectric resonator 2 to stimulate the TE of the dielectric resonator antenna. y 111 TE y 113 Similarly, the third coaxial probe 5 and the fifth coaxial probe 7 excite the TE of the dielectric resonator x 111 TE x 113 Mode.TE 111 and TE 113 The directivity patterns of the modes are similar, and the resonant frequencies are close, which increases the bandwidth of the antenna. The modes excited by the two pairs of probe groups are mutually orthogonal, realizing a pair of mutually orthogonal broadband dual-polarization radiation modes.

[0064] In summary, the three-polarization radiation mode of the antenna proposed in this embodiment is realized by feeding three feeding ports respectively, wherein the first feeding port excites a vertical polarization radiation mode with a polarization direction in the z-axis direction, and the second feeding port and the third feeding port excite a pair of horizontal polarization radiation modes with orthogonal polarization directions, and finally three mutually orthogonal polarization modes are realized in the same radiator.

[0065] like Figure 2As shown, the S parameter diagram of each port of a compact broadband low-coupled tri-polarized dielectric resonator antenna based on a non-uniform medium proposed in this embodiment. It is easy to see from the figure that the -10dB common impedance bandwidth of the proposed antenna is 1.11GHz, the operating frequency band is 1.77~2.88GHz, and the relative bandwidth is 47.7%. The isolation between the first feeding port 10 and the second feeding port 11 is 16~30dB within the operating frequency band, the isolation between the first feeding port 10 and the third feeding port 12 is 15~48dB within the operating frequency band, and the isolation between the second feeding port 11 and the third feeding port 12 is 23~34dB within the operating frequency band. In most of the operating frequency band, the isolation between the three ports is higher than 18dB.

[0066] Figure 3 The following is a diagram showing the distribution of the magnetic field size on the bottom surface of the dielectric resonator when the first feeding port of the compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium is excited separately at the operating frequencies of 1.8 GHz, 2.2 GHz, 2.5 GHz, and 2.8 GHz, respectively. It can be seen that when the frequency increases, the magnetic field energy in the resonant cavity gradually concentrates at the center, and no obvious high-order mode is generated. The antenna resonance mode is always mainly TM. 011 model.

[0067] Figure 4 and Figure 5 This is a diagram of the surface electric field distribution of a compact broadband low-coupled tri-polarized dielectric resonator antenna based on a non-uniform medium proposed in this embodiment when the second feeding port is excited separately and the third feeding port is excited separately at operating frequencies of 1.8 GHz, 2.2 GHz, 2.5 GHz, and 2.8 GHz, respectively. Figure 4 and Figure 5 It can be concluded that at the three frequency points of 1.8 GHz, 2.2 GHz, and 2.5 GHz, the proposed antenna mainly exhibits TE 111 mode; at 2.8 GHz, the proposed antenna mainly exhibits TE 113 The difference in the electric field distribution diagrams of the two ports is mainly reflected in the orthogonality of the electric field directions. It can be seen that the dual-mode resonance has a significant effect on improving the working bandwidth of the antenna.

[0068] Figure 6 to Figure 9A compact broadband low-coupled tri-polarized dielectric resonator antenna based on an inhomogeneous medium proposed in this embodiment shows radiation patterns when the first feeding port is excited individually at operating frequencies of 1.8GHz, 2.2GHz, 2.5GHz, and 2.8GHz. The XOZ plane is the antenna radiation H plane, and the XOY plane is the antenna radiation E plane. It can be seen from the H-plane radiation pattern that the radiation capability of the proposed antenna at low pitch angles is good. It can be seen from the E-plane radiation pattern that the proposed antenna also performs well in omnidirectional radiation. Combining the radiation patterns of various antennas, it can be seen that the proposed antenna has strong radiation performance at all frequencies, and the radiation patterns have no obvious directional deviation, and the vertical polarization radiation performance is strong overall.

[0069] Figure 10 to Figure 13 A compact broadband low-coupled tri-polarized dielectric resonator antenna based on an inhomogeneous medium proposed in this embodiment shows radiation patterns when the second feeding port is excited separately at operating frequencies of 1.8GHz, 2.2GHz, 2.5GHz, and 2.8GHz. The XOZ plane is the antenna radiation H plane, and the YOZ plane is the antenna radiation E plane. It can be seen from the various directional patterns that the proposed antenna has good radiation effects in all frequency points, the cross-polarization ratio is almost higher than 20dB, and the basic shape of the directional pattern is similar. The radiation direction of the directional pattern has a slight deviation from the top direction, which is caused by the asymmetric structure of the Wilkinson power divider.

[0070] Figure 14 to Figure 17 The radiation pattern of a compact broadband low-coupled tri-polarized dielectric resonator antenna based on an inhomogeneous medium proposed in this embodiment when the third feeding port is excited separately at the operating frequencies of 1.8GHz, 2.2GHz, 2.5GHz, and 2.8GHz. The third feeding port is excited in a dual relationship with the second feeding port, the XOZ plane is the antenna radiation E plane, and the YOZ plane is the antenna radiation H plane, but because the Wilkinson power dividers connected to the two ports are not exactly the same, the radiation patterns under the two excitation methods are slightly different, but the overall radiation performance is close, and both have stable radiation characteristics within the working frequency band.

[0071] The relative bandwidth of the antenna proposed by the present invention is as high as 47.7%. In most working frequency bands, the isolation between each port is higher than 18dB. The size of the dielectric block is 0.326×0.326×0.326λ0 3 , compact structure, and has obvious advantages over the existing three-polarization dielectric resonator antennas.

[0072] The tri-polarized dielectric resonator antenna proposed in this embodiment is now compared with the existing tri-polarized dielectric resonator antenna, and some key characteristics are summarized in Table 1, where λ0 represents the wavelength of the electromagnetic wave in free space at the center frequency of the antenna working frequency band. It is easy to conclude from the table that the relative bandwidth of the existing tri-polarized antenna is generally low. The main reason for the low bandwidth of the tri-polarized dielectric resonator antenna is that the bandwidth of each polarization is difficult to reach a high level at the same time, thereby maintaining a high common bandwidth, and the high coupling between each port will also limit the bandwidth performance of the antenna. In addition, the complex feeding network also has a great influence on the impedance matching of the antenna, thereby affecting the bandwidth of the antenna. Continuing to improve the bandwidth while maintaining a small size is a problem that must be overcome in the current development and application of tri-polarized antennas. Compared with the existing tri-polarized dielectric resonator antenna, the tri-polarized dielectric resonator antenna proposed in this embodiment has a compact structure, a relatively simple feeding structure, a relatively large bandwidth area, and at the same time has a higher common bandwidth, and has significant advantages.

[0073] Table 1

[0074]

Claims

1. A compact broadband low-coupling tri-polarized dielectric resonator antenna based on an inhomogeneous medium, characterized in that: include: A dielectric substrate, a dielectric resonator, a first coaxial probe, a second coaxial probe, a third coaxial probe, a fourth coaxial probe, a fifth coaxial probe, a first Wilkinson power divider, a second Wilkinson power divider, a first feeding port, a second feeding port, a third feeding port, and a floor; The dielectric substrate is arranged on the lower surface of the floor, and the dielectric resonator is arranged on the upper surface of the floor; The first Wilkinson power divider and the second Wilkinson power divider are arranged on the lower surface of the dielectric substrate; The dielectric resonator is a horizontal radial layered dielectric structure, which is composed of a cylindrical dielectric embedded in a rectangular dielectric resonator, and the dielectric constant of the cylindrical dielectric is higher than the dielectric constant of the surrounding dielectric; The first coaxial probe is inserted into the center of the dielectric resonator, and the second coaxial probe, the third coaxial probe, the fourth coaxial probe and the fifth coaxial probe are respectively inserted into the interior of the dielectric resonator and close to the edge of the dielectric resonator; Circular gaps are etched on the peripheral floors of the second coaxial probe, the third coaxial probe, the fourth coaxial probe, and the fifth coaxial probe; The second coaxial probe and the fourth coaxial probe are symmetrically arranged to form a differential feed pair, the third coaxial probe and the fifth coaxial probe are symmetrically arranged to form another differential feed pair, and the two differential feed pairs are orthogonally arranged; The first feeding port directly feeds the first coaxial probe to stimulate vertical polarization radiation TM with the polarization direction being the z-axis direction. 011 model; The second feed port is connected to the input end of the second Wilkinson power divider, and the output end of the second Wilkinson power divider is connected to a differential feed pair to stimulate TE y 111 TE y 113 Mode; the third feed port is connected to the input end of the first Wilkinson power divider, the output end of the first Wilkinson power divider is connected to another differential feed pair, and the TE is stimulated x 111 TE x 113 Mode;TE 111 and TE 113 The directional patterns of the modes are similar and the resonant frequencies are close, which increases the bandwidth of the antenna and realizes three mutually orthogonal polarization modes in the same radiator.

2. According to claim 1, a compact broadband low-coupled tri-polarized dielectric resonator antenna based on an inhomogeneous medium, characterized in that: Openings are made at the contact points between the second coaxial probe, the third coaxial probe, the fourth coaxial probe and the fifth coaxial probe and the floor.

3. The compact broadband low-coupled tri-polarized dielectric resonator antenna based on non-uniform medium according to claim 1, characterized in that: The cylindrical dielectric is at the same height as the rectangular dielectric resonator.

4. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to claim 1, characterized in that: There is a certain gap between the first coaxial probe and the dielectric resonator.

5. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to claim 1, characterized in that: The first Wilkinson power divider and the second Wilkinson power divider implement differential feeding.

6. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to claim 5, characterized in that: The first Wilkinson power divider and the second Wilkinson power divider each include a first microstrip line, a quarter-wavelength microstrip line, a second microstrip line and a limiting resistor; For any one of the first and second Wilkinson power dividers, its input end is connected to the first microstrip line, and then connected to two quarter-wavelength microstrip lines connected in parallel. A limiting resistor is connected to the ends of the two quarter-wavelength microstrip lines, and finally connected to the output end by the second microstrip line. The length of the second microstrip line connected to the two output ends differs by half of the microstrip line waveguide wavelength, so that the output signal power of the two output ends is the same and there is a phase difference of 180 degrees. The two output ends are respectively fed to symmetrical coaxial probes to achieve differential feeding.

7. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to claim 6, characterized in that: The first microstrip line and the second microstrip line are both microstrip lines with a characteristic impedance of 50 ohms.

8. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to claim 6, characterized in that: The quarter-wavelength microstrip line is a quarter-wavelength microstrip line with a characteristic impedance of 70.7 ohms.

9. The compact broadband low-coupling tri-polarized dielectric resonator antenna based on non-uniform medium according to claim 6, characterized in that: The limiting resistor is a 100 ohm limiting resistor.

Images